clear sight: a trial of non-mydriatic ultra-widefield retinal imaging to screen for diabetic eye disease

Conditions: Diabetes Mellitus; Diabetic Retinopathy

Summary: diabetic eye disease causes major vision loss in many canadians and is costly. there are effective preventions and treatments for diabetic eye disease but they strongly depend upon regular screening in asymptomatic patients. the 2013 canadian diabetes association (cda) guidelines recommend annual screening by eye care professionals, either in-person or through interpretation of dilated pupil retinal photographs. despite the benefits of screening, adherence to these guidelines is poor. reasons include patient barriers, i.e. need for eye drops, time off work, wait times, and transportation issues. an option to minimize these barriers is to screen using a camera called non-mydriatic ultra-widefield (uwf) retinal imaging. this can be quickly done without eye drops on the same day as patients' regularly scheduled diabetes clinic visits. in this study, the investigators will compare the uwf camera to the usual screening approach recommended by the cda. the investigators will invite 740 patients with diabetes due for eye screening to either be screened using the uwf camera on the day of their diabetes clinic visit or be screened by their usual eye care professional. the investigators' prediction is that same-day screening with uwf imaging will find more patients with diabetic eye disease who need treatment compared to usual screening.

in this study, the investigators are addressing a significant and expanding "care-gap" question for patients with diabetes who are at risk for diabetic retinopathy (dr). dr is a major cause of impaired health-related quality of life in ontarians through visual loss including blindness. because the prevalence of dm in ontario is increasing, the number of ontarians over age 40 years with sight-threatening dr has been projected to increase by \~ 60% by 2031. dr is also a major source of health care costs: in 2007 the estimated health care system expenditure for vision loss from dr in canada was $205 million. there are proven effective strategies to prevent and treat dr. these strategies strongly depend upon regular screening in asymptomatic patients. thus, the 2013 cda practice guidelines recommended annual eye screening by experienced eye care professionals either in-person or through interpretation of dilated pupil retinal photographs and yet, despite the benefit of screening, adherence to the cda guidelines is poor. at least part of this is due to patient-centered barriers including the need for mydriasis, time off of work, wait times, and transportation issues. recent studies indicate that non-mydriatic uwf retinal imaging minimizes these barriers and also accurately detects clinically important dr as compared to reference standard tests (dilated pupil eye exam by an eye care professional or 7-field stereoscopic colour fundus photography). in this study, the investigators' primary goal is to confirm or refute the hypothesis that screening by non-mydriatic uwf imaging at the time diabetes patients are seen for their routinely scheduled diabetes clinic visit (on-site screening) improves the rate of detection of clinically important dr as compared to usual screening by the cda guidelines. while the investigators are not testing the effect of screening by non-mydriatic uwf on visual outcomes, confirmation of the investigators' hypothesis has the potential to improve current screening strategies for dr in ontario and, with that, an expectation that this will reduce vision-threatening diabetic eye disease.

Eligibility criteria:
inclusion criteria: 1. known diagnosis of type 1 diabetes for \>/= 5 years or type 2 diabetes of any duration 2. at least 12 months since the last screening for diabetic eye disease by an eye care professional as this is based on patient self-report. subsequent confirmation of the date of the last eye examination will be obtained via communication with the patient's eye care professional. patients who indicate by self-report that it has been more than a year since screening, but in whom it is subsequently confirmed that their last screen occurred \<12 months prior to entry, will be randomized but will not be included in the primary analysis comparing on-site to usual screening. 3. provision of informed consent exclusion criteria: 1. under active followup by an ophthalmologist for dm-related eye disease. active followup requires that, at recruitment, the patient is scheduled for a future ophthalmologist appointment for any reason. 2. inability to provide informed consent. 3. any other condition or circumstance which in the judgment of the investigator makes it unlikely that the patient can adhere to the study protocol. this includes co-morbidities for which expected life-expectancy is less than a year.

Keywords: screening